This is your brain – in love

Thursday

Feb 12, 2009 at 2:00 AM

By Eliot Baker I&M Staff Writer

Don’t be surprised if Valentine’s chocolates at Sweet Inspirations are someday wrapped in brain-shaped boxes. Some fascinating insights into romance have emerged now that scientists have pinpointed Cupid’s neurological target.

While “I love you from the bottom of my brain” doesn’t sound too romantic, it deserves points for anatomical accuracy. Lucy Brown, professor of neurology and neuroscience at Albert Einstein College of Medicine, collaborated with anthropologist Helen Fisher and psychologist Arthur Aron to scan recently-smitten participants’ brains while they looked at pictures of their sweetheart and thought loving thoughts.

The results lent new gravity to the term, “Addicted to Love.” The 17 subjects showed activation in a primitive, dopamine-rich brain region called the ventral tegmental area (VTA), which is associated with cocaine highs and the body’s reward system. Other studies in China and the U.K. have confirmed the findings.

“Looking at the areas of activation, it’s very similar to people craving cocaine,” said Brown, adding that all study participants said they obsessed over their partner at least 80 percent of the day and professed a willingness to die for them. “Love is a little bit like drug addiction.”

Someone in love will crave whoever got the feel-good hormone, dopamine, to flood the VTA in the first place. The object of their desire becomes something like chocolate, money, or drugs: a goal that elicits an inner reward. Love, the team found, was more of a drive than an emotion.

Love differs from lust at several levels, including that which can be observed on an fMRI. Subjects shown erotic pictures displayed a different pattern of brain activation, indicating that lust and love are different for scientists and moralists, both.

“When men and women are sexually aroused, it’s a somewhat different part of the brain that’s active,” said Brown. “It involves parts of the hypothalamus involved with reproduction. (It is) not so clearly reward driven as is love, like learning to find food, learning to find water, learning how good food and water taste . . . It’s probably different systems.”

Sexual attraction often comes down to guessing what’s hiding in another person’s genes. For instance, people with different immune systems tend to pair up because pheromone-like scents tip each other off to complimentary MHCs, portions of chromosomes that encode disease-fighting immunity. The more varied are a couples’ MHCs, the more likely their offspring will be healthy.

The result is a fairly simple courtship equation: more pronounced sexual characteristics indicate surging sex hormones, which potentiate greater fertility, which equals: ooh, la la. (If love were a refereed sport, plastic surgery and steroids would be banned from South Beach).

Bear in mind that measures of desirability are debatable. Cultural influences on beauty and attractive behavior are tricky to gauge and can be further clouded by factors such as prestige and wealth.

Unlike lust, love springs eternal. Since sex hormones heavily influence the sex drive, their diminishment with age lowers one’s sexual urge. Not so with love, which can persist as a basic drive like thirst.

“All the evidence I have ever read and heard absolutely suggest that you can fall in love at age 80, or even 90, the same way as at 15,” said Brown. “For some people it’s easier as they get older because they are less anxious about it.”

Indeed, aging lovebirds also had VTAs that glowed on brainscans like honeymooners. But as their relationships grew more complex, so too did their brains’ reaction to long-term love. Bianca Acevedo, a post-doc at Albert Einstein who collaborated with Aron, Fisher and Brown, used similar testing methods on her 17 subjects, who were 40 to 65 years old and had been married at least 20 years.

"We see similarities and differences in terms of the pattern of activation in the brain," said Acevedo, who based her dissertation on the study. "There are similarities in the pattern of reward areas associated with being in love. But one of the differences that we find in people married many years are activation in areas associated with (the hormones) serotonin and oxytocin and vasopressin, pain suppression and calmness: to put it very broadly, those married many years and still intensely in love show activation in areas associated with calmness, with regulating our response to stress."

Incredibly, said Acevedo, long-term lovers also showed even stronger activation with the nucleus accumbens, a brain region associated with craving and euphoria in cocaine users. But the happily married couples did not display the obsessive, manic qualities of honeymoon love. Instead, they showed heightened activation of hormones associated with motherhood and nurturing like vasopressin an oxytocin.

In short, the brain scans confirmed the older couples were in love. “A great Valentine’s present would be a scan of your brain,” quipped Brown, noting that has not yet been done.

These results helped articulate the fundamental differences between obsession and love. Acevedo explained that where love is more focused on the other as part of the reward system drive, obsession focuses more on the self and is associated with anxiety, jealousy and doubt.

But romance has its risks. When love sours, the result can approximate drug withdrawal, a potentially devestating situation. In a study on rejection, Brown and Fisher placed 15 students in an fMRI and asked about their former lovers. Their brains resembled those of addicts craving cocaine.

“People came out of the MRI in tears; . . . we won’t be doing that again,” said Brown. “It was a fair amount like craving something you’re addicted to. . . These people can turn to stalking, depression, even suicide after someone has rejected them.” A better understanding of love and rejection could lead to treatments for the pain following divorce or loss of a loved one, said Brown.

Some might think that promiscuity would better serve the evolutionary purpose of spreading genes with the fittest mates. But love provides obvious survival advantages of its own, notably the extra care given to mothers and offspring.

“Any single parent will tell you it’s better when you have a partner taking care of a kid,” said Brown. “And in a way, love is more efficient. With lust you have to go out and search for mates, go to bars, and some are very successful at that, but for others it’s more efficient to have someone right there all the time.”

If today’s dating scene seems rough, imagine a world where going “clubbing” to find women meant bludgeoning another male with a cow femur. And try comparing the stress of bills and an overbearing boss with droughts and tigers. In pre-history, single mothers barely stood a chance.

Romantic love has thus endured. But Brown believes love is more than just a sum of our biological drive to advance our genes.

“The scientist in me says nature has given us certain systems to encourage survival of the species,” said Brown. “What we call romantic love is a developed form of a mammalian drive to pursue preferred mates. . . But the human side of me says nature built us to experience this magic. It’s not at a verbal level, (but) anyone who has experienced love knows it really is magic.”

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